The only "tip" I can give you is to keep your eye on the ball. You're making plans to leave, which is a clear indication that you are unhappy and that there's a good reason for it. Perhaps it would help you if you wrote down a list of things that you'll be getting away from, along with a list of things you can look forward to once you have left...keep the list handy and re-read it. LOTS.
Yes, he will no doubt thrash about, rant, rave, manipulate, cajole, threaten, etc etc. Nothing you can do about that, right? Just expect him to pull out every trick in the book, and make sure to keep any and all conversation to email, so that it can be documented. And obviously, keep all conversation on the topic of visitation and custody. Everything else is off limits. That will give you time to gain perspective, strengthen your resolve, and talk to a lawyer (or two or three).
You can do this.